1. Field of the Invention
The invention relates to a semiconductor package, and more particularly, to a radiation-shielded semiconductor package.
2. Description of the Related Art
As known in the art, radio frequency (RF) packages are sensitive to electromagnetic interference (EMI). It is therefore required to pay more attention to the crosstalk between RF packages when these RF packages are arranged on a printed circuit board.
Referring to FIG. 1, U.S. Pat. No. 6,781,231 discloses a semiconductor package 100 that includes a substrate 110 and a chip 120 disposed thereon. A cover 130 is disposed on the substrate 110 to cover the chip 120. A peripheral edge of the cover 130 is electrically connected the substrate 110 by a conductive adhesive, solder, or the like 140. The cover 130 is produced from an outer cup 132a formed from a conductive layer of material such as copper, stainless steel, aluminum, or an alloy thereof. The cover 130 further includes an inner cup 132b. The inner cup 132b is also produced from a conductive layer. An inner lining 150 is formed on the inner cup 132b. The inner lining 150 is primarily formed by conductive material. The inner lining 150 protects the chip 120 from electromagnetic interference.
The above-mentioned package has the advantage of being able to shield the chip therein from external electromagnetic interference. However, it is laborious to produce such a package.
In addition, referring to FIG. 2, U.S. Pat. No. 6,614,102 discloses another semiconductor package 10 that includes a die pad 14, a chip 12 disposed on the die pad 14 and a set of leads 16 surrounding the die pad 14, wherein the chip 12 is electrically connected to the leads 16 by bonding wires 18. In order to shield the chip 12 from electromagnetic interference, a shield element 24 is used to cover the chip 12. The shield element 24 is connected to selected leads 16, and is grounded to provide an effective electromagnetic interference shield. In order to protect the chip 12, a sealant 22 is used to encapsulate the chip 12 and bonding wire 18 to protect these elements from damage.
The above-mentioned package also has the advantage of being able to shield the chip therein from external electromagnetic interference. However, it is still required to include an additional shield element in the package. This will increase the production cost and complexity of production.
Accordingly, there exists a need to provide an EMI shielded semiconductor package to solve the above-mentioned problems.